Linear light source for enhancing uniformity of beaming light within the beaming light&#39;s effective focal range

ABSTRACT

A light guide assembly, as a linear light source, includes a light guide bar connected to a light source assembly and a reflective housing encasing the light guide bar. One surface of the light guide bar is a light-scattering/light-emission surface, and other surfaces are all reflective. The emission plane has gradually changing indentations for adjusting the light refractive and reflecting indexes to ensure the light uniformity. The reflective housing covering the light guide bar is used for enhancing the light reflection and intensity. An opening is formed in the reflective housing corresponding to the emission plane of the light guide bar, and a reflecting flange is formed at one side of the opening. Combined with the sloping and notched emission plane, light with high intensity and uniformity can be obtained, and the uniformity of beaming light within the beaming light&#39;s effective focal range can also be improved.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation-in-part of U.S. patent applicationSer. No. 10/857,873, filed Jun. 2, 2004 in the U.S. Patent and TrademarkOffice, the disclosures of which are incorporated herein by reference.

BACKGROUND OF INVENTION

1. Field of the Invention

The invention relates to a linear light source, and more particularly,to a linear light source having a light guide bar with a sloped andnotched light emitting surface and an external reflective housing, whichenhances uniformity of beaming light within the beaming light'seffective focal range in addition to the overall improvements on lightintensity and uniformity.

2. Description of Related Art

Scanners, facsimile machines and multifunction peripherals are popularlyused in daily life. This type of equipment generally utilizes a linearlight source to illuminate the target. Imaging quality of the scannedtarget is greatly related to the performance of the light source. If theintensity or uniformity of the light source is patchy, the outputpicture will not be accurate. Under certain circumstances, if thescanned target is not in a fixed focal range and exceeds the effectivefocal range tolerance of the light source, the output picture will beindistinct. Hence, the light source of the present invention with theoverall intensity and uniformity improvements and in particular theuniformity of beaming light within beaming light's effective focal rangeenhancement has been developed.

Conventional linear light sources are generally cylindrical, square orrectangular. These designs are easier to be molded or fabricated, butthe efficiency of light propagation in terms of diffusion and scatteringor uniformity control is limited. As a result, many different inventionshave been disclosed to resolve these problems. For giving considerationto linear light source designs having a symmetrical polygonal cylinder,the applicant has previously developed a linear light source having areflecting plane. As shown in FIG. 1, the light source comprises a lightguide bar 40′ and a light source component 50′. The light guide bar 40′is a polygonal cylinder, and includes an arced emission plane 42′, areflecting plane 44′ corresponding to the arced emission plane 42′, anincidence plane 46′ and a plurality of reflecting sides 48′. With thiskind of design, the light guide bar 40′ can yield uniformed light withthe reflecting plane 44′ after directing the light from the lightemitting diode on the light source component 50′. Also, the condensingeffect of the arced emission plane 42′ can lead to better light outputand enhance the image detecting quality.

The above-mentioned prior art utilizes the plane treatment of the lightguide bar to improve the light uniformity, and changes the structure ofthe light guide bar to improve the condensing effect and lightintensity. Although the prior art provides acceptable results, greaterimprovements are still sought after to optimize the energy conservation,improve the intensity and uniformity of the emitted light, and enhancethe uniformity of beaming light within beaming light's effective focalrange. Hence, the present invention discloses a linear light sourcehaving a sloped and notched light-emitting surface and an externalreflective housing which enhances uniformity of beaming light within thebeaming light's effective focal range. The reflecting housing withreflecting flange efficiently guides the light and reduces the energyloss with repetitive diffusion and scattering, thus further enhancingthe light intensity.

SUMMARY OF INVENTION

It is therefore an objective to provide a linear light source that canbe applied to the target in order to improve the definition and accuracyof scanning.

It is therefore another objective to provide a linear light source forenhancing the uniformity of beaming light within the beaming light'seffective focal range.

It is therefore a further objective to provide a linear light sourcewith greater emitted or beaming light uniformity that can accuratelydetect the target without loss caused by uneven or non-uniformintensity.

It is therefore a further objective to provide a linear light sourcewith high intensity that can repeatedly reflect light in order tooptimally conserve the light energy and greatly enhance the intensity.

The present invention discloses a light guide assembly with improvedintensity, uniformity and enhanced uniformity of beaming light withineffective beaming light focal range. The light guide assembly comprisesa light guide bar that connects to a light source assembly. The lightsource assembly comprises, for example, a single LED or plurality ofLEDs in an LED package. The light source is positioned adjacent to alight-receiving end of the light guide bar. The light guide bar isencased in a reflective housing such as a reflective sleeve orreflective windowed box. One surface of the light guide bar is alight-scattering/light-emission surface where the light exits.

The reflective housing surrounds all surfaces except for thelight-scattering/light-emission surface. The reflective housing may be awindowed box wherein the light guide bar is enclosed in the box exceptfor the light-emitting surface, which emits light through the opening orwindow of the box. The surfaces of the light guide bar surrounded by thereflective housing are reflective surfaces for reflecting light.

After light from the light source assembly enters the light-receivingend or ends of the light guide bar, the light may be reflected off anyof the reflective surfaces. The light eventually exits the light guidebar through the light-scattering/light-emission surface. Thelight-scattering/light-emission surface further comprises alight-scattering pattern that serves to diffuse the light. Thelight-scattering pattern can comprise a series of notches and/or ridgesthat are formed such that they vary along the length of the light guidebody and may be slightly ramped or sloped from a side view.

As mentioned above, the light-scattering pattern diffuses the lightsince the light is reflected by one or more of the notches or ridges.The light continues to propagate through the light guide bar from thelight-receiving end toward the opposite end before exiting the surfaceeither through a notch or ridge. The light exiting thelight-scattering/light-emission surface also refracts at a variety ofdifferent angles through the various notches and ridges.

These and other objectives of the present invention will no doubt becomeobvious to those of ordinary skill in the art after reading thefollowing detailed description of the preferred embodiment that isillustrated in the various figures and drawings.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a 3-dimentional diagram of a prior art linear light source;

FIG. 2 is a 3-dimentional diagram of a light guide assembly according toan embodiment of the present invention;

FIG. 3 is an exploded view of a light guide assembly according to anembodiment of the present invention;

FIG. 4A is a cross-sectional view of a light guide assembly according toan embodiment of the present invention;

FIG. 4B is a cross-sectional view of a light guide assembly according toan embodiment of the present invention;

FIG. 4C is a cross-sectional view of a light guide assembly according toan embodiment of the present invention;

FIG. 4D is a cross-sectional view of a light guide assembly according toan embodiment of the present invention;

FIG. 5 is a front view of a light source of a light guide assemblyaccording to an embodiment of the present invention;

FIG. 6 is a side view of a light-scattering pattern of alight-scattering/light-emission surface according to an embodiment ofthe present invention;

FIG. 7 is a side view of a light-scattering pattern of alight-scattering/light-emission surface according to an embodiment ofthe present invention;

FIG. 8 is a graph illustrating testing results of intensity without areflecting flange according to an embodiment of the present invention;

FIG. 9 is a graph illustrating testing results of intensity with areflecting flange according to and embodiment of the present invention;

FIGS. 10A-10C are cross-sectional, 3-dimensional, and side views of alight guide bar according to an embodiment of the present invention;

FIGS. 10D-10E are side views of a 4 pin and 8 pin LED package accordingto an embodiment of the present invention;

FIGS. 11A-11B are cross-sectional and 3-dimensional views of a lightguide bar according to an embodiment of the present invention; and

FIG. 12 is a cross-sectional view of a light guide bar according to anembodiment of the present invention.

DETAILED DESCRIPTION

The present invention provides a light guide assembly with improvedemitted light intensity and uniformity and with improved uniformity ofbeaming light within the beaming light's effective focal range.

Refer to FIG. 2, which is a 3-dimentional diagram of a light guideassembly according to an embodiment of the present invention.

As shown in FIG. 2, the light guide assembly 1 comprises a light sourceassembly 10, a light guide bar 20 and a reflecting sleeve 30 surroundingthe light guide body 20. Light from the light guide bar 20 is emittedthrough an emission opening 32 in the reflecting sleeve 30.

Also refer to FIG. 3, which is an exploded view of a light guideassembly according to an embodiment of the present invention.

The light source assembly 10 of the light guide assembly 1 comprises anopening 12 which corresponds in shape to the shape of the light guidebar 20. The light guide bar 20 is received in the opening 12 and allowsthe light guide bar 20 to firmly connect to the light source 10. Atleast one light emitting diode (LED) 14 is installed in the opening 12of the light source assembly 10 as the light source origin. The lightguide bar 20 is a symmetrical polygonal cylinder and is illustrated asan octagonal cylinder in this embodiment. However, the number of sidesof the light guide body can be chosen as desired. The light guide bar 20is primarily used for converting the spot light source of the LED 14into a linear light source. One surface of the light guide bar 20 is alight-scattering/light-emission surface 22 for linearly emitting thelight. The other surfaces are reflecting surfaces 24 used for reflectingthe light. One end of the light guide bar 20 is a light-receiving end26. When the light source assembly 10 and the light guide bar 20 areassembled together, the light-receiving end 26 corresponds to the LED 14of the light source assembly 10, so that the light from the LED 14passes into the light guide bar 20 via the light-receiving end 26 and isdistributed through the structure of the light guide bar 20.

Furthermore, the reflective sleeve 30 covers the light guide bar 20thereby enhancing the reflection effect and improves the outputintensity. An emission opening 32 is formed in the reflective sleeve 30corresponding to the light-scattering/light-emission surface 22 of thelight guide bar 20 for allowing the light to pass. The other surfacesare reflective surfaces 24 and are covered by the reflective sleeve 30.After entering the light guide bar 20, the light is reflected by thereflective surfaces 24 and the reflective sleeve 30 in order to enhancethe intensity. After being reflected the light will be emitted throughthe emission opening 32 from the light-scattering/light-emission surface22. In the design, the reflective sleeve 30 can further comprise anupper section 34 and a lower section 36. The light guide bar 20 isplaced between the upper section 34 and the lower section 36, and withthe combination of the upper and lower sections 34, 36, the light guidebar 20 will be encased in the reflective sleeve 30. Since the primaryfunction of the reflective sleeve 30 is to reflect the light, the colorof the reflective sleeve 30 can be selected from those having greaterreflectivity, such as white, silver, or silvery white.

Refer to FIG. 4A, which is a cross-sectional view of a light guideassembly according to an embodiment of the present invention.

For enhancing the reflection effect, a reflecting flange 38 is locatedon the lower section 36 at one side of the emission opening 32. Theangle between the reflecting flange 38 and the vertical axis of theemission opening 32 is typically about 30 to 60 degrees. However theangle, length, and width of the reflecting flange 38 can be modifiedaccording to requirements. Because the emission angle of the lightoutput by the light guide bar 20 via the light-scattering/light-emissionsurface 22 is in a wide range and not directed toward the target 40, thereflecting flange 38 can reflect and redirect the light once again.

The addition of the reflective flange 38 further aids in concentratingthe light, optimally conserving the light energy, and improving theoutput intensity and overall uniformity.

Refer to FIG. 4B, which is a cross-sectional view of a light guideassembly according to an embodiment of the present invention.

In some embodiments, the reflecting housing comprises a one piece or twopiece reflecting sleeve 34, 36. In application, after the light guidebar 20, light source assembly, and reflecting sleeve 34, 36 areassembled, the light guide assembly is mounted in a larger mounting base400.

Refer to FIG. 4C and FIG. 4D, which are cross-sectional views of a lightguide assembly according to an embodiment of the present invention.

In other embodiments such as illustrated in 4C, the larger mounting baseis made of a reflective material such as white, silver, or white-silvermaterial. In this way, the larger mounting base becomes the reflectinghousing 400. The light guide bar 20 and the light source assembly aremounted into the reflecting housing 400 without the need for alsoassembling a separate reflective sleeve. This eliminates productionsteps and lowers production costs.

Additionally as shown in FIG. 4D, a reflecting housing top section 34Bcan be optionally installed on top of the reflecting housing 400 afterthe light guide bar 20 is installed. This further adds to the reflectivefunction of the reflecting housing 400. Refer to FIG. 5, which is afront view of a light source assembly of a light guide assemblyaccording to an embodiment of the present invention.

The LED 14 can be selected from a red LED, blue LED or green LED, othercolor of LED in accordance with the user's requirement. When requiring amonochromatic light source, only one color of LED needs to be placed inthe base of the light source assembly 10, and when requiring a colorlight source, a light emitting diode or a plurality of light emittingdiodes of any color within the visible light spectrum or near visiblelight spectrum such as infrared or ultraviolet are installed. In thisexample, three LEDs are utilized. However, any number of, color of, orcombination of LEDs can be utilized or configured as required.

However, due to the different color and different wavelength of theLEDs, the LEDs 14 are installed at a position approximately 1.12±0.1centimeters in a diametrical range outward from the center of theopening 12. Furthermore, the distance from the center or positioning ofthe LEDs can be modified to meet requirements. When the light guide bar20 and the opening 12 are securely connected, the light of each LED canconcentratively enter the light guide bar with a reduced invalidreflecting region.

Refer to FIG. 6 and FIG. 7, which are side views of a light-scatteringpattern of a light-scattering/light-emission surface according to anembodiment of the present invention.

In order to improve intensity and increase uniformity, in someembodiments the light-scattering/light-emission plane 22 is sloped andnotched. The present invention forms the notches on the surface of thelight-scattering/light-emission surface 22. If the notches are formed onthe reflective plane, the light is output after being reflected andrefracted in the light guide body. Although this can also improve theuniformity, the residual notch or indentation shadow will be obviousafter exceeding a certain range. Therefore, it is preferred to form thenotches on the light-scattering/light-emission surface. As a result, thepresent invention not only reduces the influence or shadow of theindentations or notches but also improves the uniformity. The light isreflected and refracted by the reflective surfaces of the light guidebar and the reflective housing, and then output from thelight-scattering/light-emission surface. With different notch angles,the light can be controlled more uniformly. Because the light isdirectly output after being uniformed, the indentation shadow is notobvious, and the effective focal range tolerance of the light can alsobe improved when combined with the reflective flange.

In the present invention, the design of the notches or indentations isclosely related to the light uniformity. The incline angle (θ) of thenotch is typically between 0.03 to 0.15 degrees, and the angle can begradually or sectionally increased. For example as shown in FIG. 7, theincline angle of section I is a fixed value between 0.03 to 0.09 degrees(such as 0.07), and the incline angle of section II is a fixed valuebetween 0.09 to 0.15 degrees (such as 0.11). If illustrated byincreasing the incline angle over 3 sections, the incline angle ofsection I could be a fixed value between 0.03 to 0.05 degrees (such as0.04), the angle of section II could be fixed value between 0.05 to 0.10degrees (such as 0.08), and the angle of section III could be a fixedvalue between 0.10 to 0.15 degrees (such as 0.12). Obviously, otherangles of incline can be utilized depending on requirements. Forexample, the incline angle can be linearly or logarithmically increasedfrom one end to the other.

Following is a method for calculating the height and the incline lengthof the notches or indentations formed in thelight-scattering/light-emission surface, as shown in FIG. 6. Assume thesection has the same incline angle (θ), L is the total length of theconcentrated effective focal range of the LED in this section, thedistance between the bottoms of each notch are the same, N is the lengthfrom the calculated indentation to the concentrated focus of the LED(typically between 1-111), and the angle of the indent is φ (typicallybetween 30 to 40 degrees). $\begin{matrix}{{{So},{{{the}\quad{height}\quad{of}\quad{the}\quad 1{st}\quad{indent}\quad{X1}} = {\left( {L - {N1}} \right)*\tan\quad\theta}}}\quad{{{the}\quad{height}\quad{of}\quad{the}\quad 2{nd}\quad{indent}\quad{X2}} = {\left( {L - {N2}} \right)*\tan\quad\theta}}\quad\vdots} & (1) \\{{{and},{{{the}\quad{incline}\quad{length}\quad{of}\quad{the}\quad 1{st}\quad{indent}\quad{Y1}} = {{{X1}/\sin}\quad\varphi\quad 1}}}\quad{{{the}\quad{incline}\quad{length}\quad{of}\quad{the}\quad 2{nd}\quad{indent}\quad{Y2}} = {{{X2}/\sin}\quad\varphi\quad 2}}\quad\vdots} & (2)\end{matrix}$

In equations (1) and (2), the height of the indent can be calculated andthen the incline length of the indent can be also obtained. By usingdifferent values of N and φ, the incline length of the indent can bechanged to control the light refractive index and reflecting index.

Refer to FIG. 8, which is a graph illustrating testing results ofintensity without a reflective flange and FIG. 9, which is a graphillustrating testing results of intensity with a reflective flangeaccording to and embodiment of the present invention.

With the same green light source, and input duty of 0.24, the outputintensity without the reflecting flange is about 0.9288V, and with thereflecting flange the output intensity can be raised to 1.5432V. Thisproves that the present invention can effectively improve the lightoutput intensity by adding the reflecting flange. Combined with thenotched light-scattering/light-emission surface, a light with highintensity and uniformity can be obtained, and the beaming lighteffective focal range tolerance can be also enlarged. In application, animage output with greater quality and resolution can be accomplished.

Refer to FIGS. 10A-10C, which are cross-sectional, 3-dimensional, andside views of a light guide bar according to an embodiment of thepresent invention.

In an embodiment of the present invention, the light guide bar 1000 isan elongated polygon. A light-scattering/light-emission surface 1010 isdisposed on one surface having a light-scattering pattern. The othersurfaces act as light-reflecting surfaces.

Since the light guide bar 1000 is symmetrical, it can be rotated 180degrees so that the light-scattering pattern is no longer on thelight-emission surface but rather on the surface directly opposite thelight-emission surface.

This allows the light guide assembly to be flexibly adapted according toneeds or requirements. For example, if the light-scattering pattern ison the light-emission surface, a low power or less expensive LED lightsource can be used. If less light is desired, the light bar can berotated so that the light-scattering pattern is 180 degrees from thelight-emission surface. This allows manufacturers to tune or adjust theamount of light.

In another embodiment of the present invention, the light guide bar 1000comprises two light-scattering patterned surfaces. One surface is thelight-emission surface 1010 and 180 degrees opposite is a patternedlight-reflecting surface 1020.

This configuration provides ease during assembly since the light guidebar cannot be installed in the incorrect orientation.

Refer to FIG. 10D-10E, which are side views of a 4 pin and 8 pin LEDpackage according to an embodiment of the present invention.

FIGS. 10D-10E illustrate LED packages 1050A, 1050B that can be used withthe light guide bar illustrated in FIGS. 10A-10C. In FIG. 10D, the LEDpackage 1050A is a 4 pin LED package. This allows three LED lightsources to be installed in an opening 1060 of the LED package housing.The four pins 1070 allow power and common ground to be provided to theLEDs.

Similarly, in FIG. 10E, the LED package 1050B is an 8 pin LED package.This allows up to 7 LED light sources to be used.

Refer to FIGS. 11A-11B, which are cross-sectional and 3-dimensionalviews of a light guide bar according to an embodiment of the presentinvention.

In another embodiment of the present invention, the light guide bar 1100is extended pentagon shaped. The light guide bar 1100 comprises alight-emission surface 1110 with a light-scattering pattern on thesurface. An opposite side from the light-emission surface 1110 is alight-reflecting surface 1120. In an embodiment of the present inventionthe light-reflecting surface 1120 has a smooth or rough surface. Inanother embodiment of the present invention the light-reflecting surfacehas a light-scattering pattern similar to the light-emission surface1110.

Refer to FIG. 12, which is a cross-sectional view of a light guide baraccording to an embodiment of the present invention.

In this embodiment, as illustrated in FIG. 12, the light guide bar 1200is shaped as another type of elongated polygon. The light guide bar 1200comprises a light-emission surface 1210 with light-scattering patternand a light-reflecting surface 1220.

It should be noted that in the embodiments described above, thelight-scattering pattern can be adjusted to suit various requirements.For example, on the end of the light guide bar nearest the light source,the notches of the pattern can be eliminated for the first 20 or 30 mmand replaced with a rough texture on the surface.

Additionally, LED light sources are selected from any color within thevisible light spectrum or near visible light spectrum such as IR or UV.For example, the LEDs can be green, yellow, blue, red, white, etc. Thisallows the linear light assembly to emit a wide variety and amount oflight.

Those skilled in the art will readily observe that numerousmodifications and alterations of the device may be made while retainingthe teachings of the invention. Accordingly, the above disclosure shouldbe construed as limited only by the metes and bounds of the appendedclaims.

1. A light guide assembly for enhancing uniformity of beaming light,comprising: a light guide bar comprising a light-emission surface and aplurality of reflecting surfaces, wherein the light-emission surfacecomprises a plurality of notches; a light source assembly connecting tothe light guide bar, the light source assembly comprising at least onelight emitting diode; and a reflective housing encasing a portion of thelight guide bar, and a reflecting flange on the reflective housing forreflecting light emitted from the light-emission surface.
 2. The lightguide assembly for enhancing uniformity of beaming light of claim 1, thelight source assembly further comprising a base with an openingcorresponding to a shape of the light guide bar for connecting the lightguide bar and the light source assembly.
 3. The light guide assembly forenhancing uniformity of beaming light of claim 1, wherein the lightemitting diode comprises at least one light emitting diode of any colorwithin visible or near visible light spectrum.
 4. The light guideassembly for enhancing uniformity of beaming light of claim 2, whereinthe light emitting diode is positioned 1.12±0.1 centimeters in adiametrical range outward a center of the base opening.
 5. The lightguide assembly for enhancing uniformity of beaming light of claim 1,wherein the notches are formed on an outer surface of the emissionplane.
 6. The light guide assembly for enhancing uniformity of beaminglight of claim 1, wherein the reflective housing comprises an uppersection and a lower section, wherein the upper and lower sections can becombined together.
 7. The light guide assembly for enhancing uniformityof beaming light of claim 1, wherein an angle between the reflectingflange and a vertical axis of the emission opening is 30 to 60 degrees.8. The light guide assembly for enhancing uniformity of beaming light ofclaim 5, wherein an angle of the notched surface is gradually increasedwith an incline angle of 0.03 to 0.15 degrees.
 9. The light guideassembly for enhancing uniformity of beaming light of claim 5, whereinan incline angle of the notched plane is gradually and segmentallyincreased.
 10. The light guide assembly for enhancing uniformity ofbeaming light of claim 1, wherein a color of the reflective housing isselected from one of white, silvery-white and silver.
 11. A light guideassembly for enhancing uniformity of beaming light, comprising: apolygonal cylindrical light guide bar, wherein one surface of the lightguide bar is a light-scattering/light-emission surface and othersurfaces are a plurality of reflecting surfaces, and at least one end ofthe light guide bar is a light-receiving end, wherein thelight-scattering/light-emission surface comprises an indented surface; alight source assembly connecting to said light guide bar, wherein saidlight source assembly includes at least one light emitting diode; and areflective housing encasing said light guide bar, and an emissionopening in the reflective sleeve formed corresponding to thelight-scattering/light-emission surface.
 12. The light guide assemblyfor enhancing uniformity of beaming light of claim 11, wherein theindented surface is a gradually indented surface formed on an outsidesurface of the light-scattering/light-emission surface.
 13. The lightguide assembly for enhancing uniformity of beaming light of claim 11,wherein an opening is formed in the light source assembly correspondingto a shape of the light guide bar for fastening the light guide bar tothe light source assembly.
 14. The light guide assembly for enhancinguniformity of beaming light of claim 11, wherein a reflecting flange isformed at one side of the emission opening.
 15. The light guide assemblyfor enhancing uniformity of beaming light of claim 11, wherein the lightemitting diode comprises at least one light emitting diode of any colorwithin visible or near visible light spectrum.
 16. The light guideassembly for enhancing uniformity of beaming light of claim 13, whereinthe light emitting diode is placed at a distance of 1.12±0.1 centimetersin diametrical range outward from a center of the opening.
 17. The lightguide assembly for enhancing uniformity of beaming light of claim 11,wherein the reflective housing further comprises an upper sleeve and alower sleeve, the upper and lower sleeves can be combined together. 18.The light guide assembly for enhancing uniformity of beaming light ofclaim 11, wherein an angle between the reflecting flange and a verticalaxis of the emission opening is 30 to 60 degrees.
 19. The light guideassembly for enhancing uniformity of beaming light of claim 12, whereinan angle of said indented surface is gradually increased with an inclineangle of 0.03 to 0.15 degrees.
 20. The light guide assembly forenhancing uniformity of beaming light of claim 12, wherein the inclineangle of the indented surface is gradually and segmentally increased.21. The light guide assembly for enhancing uniformity of beaming lightof claim 11, wherein a color of the reflective housing is selected fromone of white, silvery-white and silver.
 22. A light guide assembly forenhancing uniformity of beaming light, comprising: a polygonal lightguide bar, wherein one surface of the light guide bar is an emissionsurface and other surfaces are a plurality of reflecting surfaces, atleast one end of the light guide bar is a light-receiving end, whereinthe emission plane comprises an indented surface; a light sourceassembly connecting to said light guide bar, wherein the light sourceassembly comprises at least one light emitting diode; and a reflectivehousing encasing the light guide bar, an opening is formed in thereflective housing corresponding to the emission surface and areflecting flange is formed at one side of the opening.
 23. The lightguide assembly for enhancing uniformity of beaming light of claim 22,wherein the indented plane comprises notches of more than one depth. 24.The light guide assembly for enhancing uniformity of beaming light ofclaim 22, wherein a base opening is formed in the light source assemblycorresponding to a shape of the light guide bar for connecting the lightguide bar and the light source assembly.
 25. The light guide assemblyfor enhancing uniformity of beaming light of claim 22, wherein the lightemitting diode comprises at least one light emitting diode of any colorwithin visible or near visible light spectrum.
 26. The light guideassembly for enhancing uniformity of beaming light of claim 24, whereinthe light emitting diode is placed at a distance of 1.12±0.1 centimetersin a diameter range outward of a center of the base opening.
 27. Thelight guide assembly for enhancing uniformity of beaming light of claim22, wherein the reflective housing further comprises an upper sleeve anda lower sleeve, and the upper and lower sleeves can be combinedtogether.
 28. The light guide assembly for enhancing uniformity ofbeaming light of claim 22, wherein the angle between said reflectingflange and a vertical axis of the opening is 30 to 60 degrees.
 29. Thelight guide assembly for enhancing uniformity of beaming light of claim23, wherein the angle of the indented plane is gradually increased withan incline angle of 0.03 to 0.15 degrees.
 30. The light guide assemblyfor enhancing uniformity of beaming light of claim 22, wherein a colorof the reflective housing is selected from one of white, silvery whiteand silver.